Microsporidia MB (MB), a promising biological control agent, suppresses Plasmodium falciparum transmission in Anopheles mosquitoes. This study examined the spatial distribution of MB infection in natural populations of An. gambiae s.l. mosquitoes collected in Nigeria and Niger Republic, and its association with insecticide susceptibility in the mosquitoes. Microsporidia MB has wide geographic distribution across Nigeria and Niger Republic. The overall prevalence of MB in F₀ mosquitoes was 12.25% (95% CI: 7.76–16.75%); 25 mosquitoes out of 204 were positive. Geographic variation was observed, with a higher prevalence (5/15 mosquitoes) in Ebonyi State (33.33%, CI: 9.48–57.19%, Fisher’s exact test, p = 0.008). Infection rates were higher in An. coluzzii mosquitoes (21/133 mosquitoes), estimated at 15.79% (CI: 9.59–21.99%) compared to An. gambiae s.s. mosquitoes (4/71), with approximately 5.63% (CI: 0.27–11.00%, χ² = 4.44; df = 1, p = 0.035). Resistant mosquitoes had a significantly higher prevalence of MB infection than susceptible mosquitos at 28.57% (CI: 16.74–40.40%) with an odds ratio of 3.33 (CI: 1.23–9.03, p = 0.017). These findings suggests that MB can be exploited as an alternative for vector control in Nigeria and Niger, but its possible association with pyrethroid resistance suggests that it should be taken into account as a potential confounder when designing insecticide resistance management strategies.

Samples of beans and rice were collected from five Local Government Areas (LGAs) of Gombe State for the quantitative determination of glyphosate residues. The residue extraction was performed using acetonitrile/water (50/50%) solution and the extracts were injected into the injection block of gas chromatography in tandem with a mass spectrophotometer for separation and quantification. The concentrations of glyphosate in bean samples ranged between 0.0164 mg/kg and 0.0508 mg/kg higher than the residues found in rice samples between 0.0175 mg/kg and 0.0434 mg/kg. The highest concentration of glyphosate residues in beans was 0.0508±0.01 mg/kg from Gombe LGA while the rice sample from Akko LGA was highest with 0.0434±0.02 mg/kg. Both samples in all the LGAs were found to be lower than their respective Maximum Residual Limits (MRLs) and lower than the Acceptable Daily Intake (ADI) of 0.5mg/kg/day. Health Index, HI < 1 was obtained in all samples; indicating that the residues in the grains do not pose any threat to the exposed population. However, the Cancer Risk Index, CRI for children were 7.32x10-4 and 4.090x10-4while those for adults were 9.140x10-2 and 5.120x10-4 for beans and rice respectively. The TCRI for children and adults were 1.140x10-3 and 6.030x10-4 respectively. These are indications that the exposed population is at high risk, with the children more susceptible, probably due to low body weight. The study, therefore, suggests strict monitoring of the use of glyphosate-based herbicides to curtail or minimize the risk of possible bioaccumulation in the body and also calls on further studies on human urine and blood samples of farmers within the study area for further toxicological studies.

Background: Microsporidia MB (MB), a promising biological control agent suppresses Plasmodium falciparum transmission in Anopheles mosquitoes. Methods: This study examined the spatial distribution of MB infection in natural populations of An. gambiae s.l. mosquitoes collected in Nigeria and Niger Republic, and its potential modulation of insecticide susceptibility in the Anopheles mosquitoes. Results: The overall prevalence of MB in F₀ mosquitoes was 12.25% (95% CI: 7.76%-16.75%); 25 mosquitoes out of 204 were positive. Geographic variation was observed, with a higher prevalence (5/15 mosquitoes) in Ebonyi State (33.33%, 95% CI: 9.48%-57.19%, Fisher's exact test, p = 0.008). Infection rates were higher in An. coluzzii mosquitoes (21/133 mosquitoes), estimated at 15.79% (95% CI: 9.59%-21.99%) compared to An. gambiae s.s. mosquitoes (4/67), approximately 5.63% (95% CI: 0.27%-11.00%), χ² = 4.44; df = 1, p = 0.035)]. Resistant mosquitoes had a significantly higher prevalence of MB infection at 28.57% (95% CI: 16.74%-40.40%) and OR of 3.33 (95% CI: 1.23-9.03, p = 0.017) compared with susceptible mosquitoes. Conclusion: MB has wide geographic distribution across Nigeria and Niger Republic. An. coluzzii and resistant mosquitoes are more infected with this fungi. Understanding the geographic and species-specific infection patterns and implication in insecticide resistance could guide targeted vector control strategies using this biological agent.